Foot dimmer switch operating mechanism



July 29, 1952 G, s. ELLITHORPE FOOT DIMMER SWITCH OPERATING MECHANISMFiled Dec. 30, 1949 FIG.5

IW V HM' v INVENTOR.' GTLBERT s. ELLITHORPE* BY L 2'- Patented July 29,1952 FOOT -DIMMER SWITCH OPERATING MECHANISM Gilbert S. Ellithorpe,Chicago, Ill.,g assignor yto Carter Parts Company, Chicago, Ill., acorporation of Illinois ApplicationDecember 30,1949-,SerialNo.136,-0`37y Y y s achim-s. (cina-10b) This invention relates to snap-acting switchmechanisms and particularly to a plunger actuated rotary-switchoperating means such as may be employedv to operate a dimmer switch usedin the head-light circuit of a motor vehicle.

The ymain objects of this invention are to vprovide an improvedsnap-acting switch operating mechanism; to provide an improvedplunger-actuated snap-acting rotary switch operating means.; to providean improved operating rotor forsnap-acting rotary switches; and toprovide an--improvedfarrangement and construction for controlling theoperation of a, snap-acting rotor in such devices which will result in agreatly increased useful life for the operating parts.

A specic embodiment of this invention is shown in the accompanyingdrawings in which:

Figure 1 is a perspective view of a switch operatingmechanism embodyingthe invention, the view being partly broken away to illustratev thearrangement of the actuating means.

Fig. y2 is a plan View of the same partly in section, the view showingthe plunger and the rotary element in neutral position.

Fig. 3 is a fragmentary plan view of the same showing the rotary elementand actuating parts inthe rst position of operation. Y

Fig. 4 is a similar view showing the rotor in almost mid position andjust prior to its release for snap action.

Fig. 5 lis a similar view showing the par-ts immediately after the rotorhas been snapped to its changed position. l

Fig. 6 is a. similar view showing the operating elements in neutralposition when actuation of the mechanism has been completed.

Fig. 7 is a sectional view of the device as taken on line 'I-1 of Fig.6, illustrating the manner in which the rotor is mounted and therelationship of the trip lever or operating finger with the rotor,. and

Fig. 8l is a sectional view of the same as taken on line 8-8 of Fig. 6.

In the form shown in the drawings, the improved switch operatingmechanism comprises a vhollow box-like body I having a hollow neck orextension 2 projecting from one side, the neck or'extension being openat its outer end and having communication with the box-like body I atits `inner end through a slot-like opening 3 inthe body side wall.Arotor or carrier plate 4 is pivotally 4mounted within the body I on afixed stud 5, which in turn is mounted on the bottom wall of the body Isubstantially at its center, and aviiatreciprocable plunger bar B, whichextends through the neck 2 into n the 'slot.3, is disposed below therotor 4`bet`ween the rotor vand the bottom wall of the housing@` Theplunger bar 6 extends beyond the pivotpo'st or stud 5 and a longitudinalslot 1, through which the body of the pivot stud 5 extends, 4is formedadjacent the inner end of the plunger bar., Y, y

The plunger bar 6 extends throughr theneck 2. and beyond the outer endof the same, where it is attached to a cup-like cap member 8 'adapted toiit slidably over' the end ofthe neck 2;Nand a coiled compression spring9 is mounted within the neck 2, to bear between the end of the plunger,

cap 8 and the wall of the housing I'.'so as to nor- -V mally urge theplunger bar 6 in an outward direc-f` tion, the outward xnove'mentV ofthe plunger bar 6 being limited by engagement of.V the yfar 0r inV` nerend of the slot 1 with the pivot stud 5. j.

As shown in Figs. 1 'and 2, the plunger bar Vli carries a trip lever oroperating finger I0, which lies longitudinally parallel with the plungerbai' and extends int'o the housing I through the slot Sand this tripiing'er is disposed on the upper side of the plunger bar 6 so as to liein substantially the same plane as the rotor 4. The trip levery IIJ ismounted on the plunger bar 6 by mean'sfot a pair of laterally spaced endng'ers II, which are turned at right angles to the trip lever and whichstraddle a reduced portion I2 of the plunger bar adjacent the outer endthereof, the' reduced portion I2 being of suflcint length t. allowlimitedV longitudinal 'movement of th triplvi" relative to the plungerbar.

As shown a cup washer I3 isr dis'psd li'f the outer end fof the triplever I0, so as to ba'ij against the end fingers II, to receive one endfa second` compression spring I4, nested 'within the first compressionspring 9,' which bears be'- tween the cup washer I3 and the endo'f thplunger cap .y This spring I4fnr-inally iig's'. the trip lever forwardlytoward thertor 4 and longitudinally o f the plunger bar. The fingers I Iat the.y outer end of the trip lever vare suicientl-y spaced laterallytoloosely straddle the ifducd portion I2 of the plunger bar and thus thetrip lever I0 is swingable, to a limited extent, in either directionlaterally of the vplunger bar centei'f. line. The inner spring I4normallyhldsthe lever in the central position with respect tothe plungerbar, and yields slightly o'n one side or the other when force is appliedto the free end of the trip leverl to cause it to swing` laterally.

As shown in the drawings, the rotor or carrier 4 comprises a flat metalbody having *a central hub portion anda pairof diametricallyopthenhousi'ng I by wayfof posite wing portions projecting laterallyfrom the hub. This body is provided with a pair of angularly spacedV-shaped seats I5 and I6, in its margin nearest the inner end of thetrip lever I0, which seats are formed by notches made in the rotormargin at locations equally spaced on either side .of aline'intersecting the rotor axis at right angles to the wing portions.The adjacent margins or edges of the seats I5 and I intersect orconverge inwardly to form a triangular projection or tooth Il, whichseparates and defines the seats and also serves as a center guide tolead the free end of the trip lever into one or the other of the seatsas the lever is moved toward the rotor. Also, the rotor 4 is providedwith an integral rhombus-shaped cam I8 on its opposite margin, which camis located diametrically opposite the tooth or projection II and engagesan upstanding tongue or stop lug I9 formed on the inner end of theplunger bar 6. This stop lug vlocks the carrier or rotor againstturning, by engagement at the base of the cam I8, until theplunger bar 6is moved inwardly a suiiicient distance to disengage the stop lug fromthe cam.

Thus when the plunger bar 6 is pushed inwardly, by means of pressureexerted on the cap 8 against the action of the spring 9, the inner endvof the trip lever Hi, under pressure from theSpringA I4, is broughtinto engagement with the tooth I'I on the rotor 4 and its free end isswung laterally, by the adjacent one of the inwardly diverging walls ofthe tooth, and seated in. the .nearest one of the seats I5 and I6, therotor 4 always being turned to one side or the other when the plunger isin its released or neutral position as shown in Figs. 2 and 6. Thisengagement of the trip lever in one or the other of the rotor seats willexert a turning or torque force on the rotor because of the fact thatthe seats are located laterally with respect to the axis of the rotorand the longitudinal centerline of the plunger bar 6. Turning of therotor, however, is restrained by engagement of the stop lug I9, on theinner. end of the plunger bar, with the rhombic or diamond-shaped cam I8and the trip lever must, therefore, yield rearwardly along the plungerbar, against the action of the spring I4, until the stop lug I9 iscarried beyond the end of the cam I8 by inward movement of the plungerbar. At the instant that the cam is released from the stop lug the triplever I0, under the stored up tension of its spring I4, will immediatelymove forwardly along the plunger bar and .cause the rotor to swing orturn suddenly, with a snap action, in the direction opposite the sideengaged by the trip lever.

The mechanism thus far described, for imparting the snap-action turningmovement to the rotor, has been used for many years in the operatingmechanism for automotive foot dimmer switches. However, in this priormechanism, the cam, by which the turning of the rotor was restrained,was of the beaver-tail type having a broad outer end surface andoutwardly diverging sides, and the stop lug of the plunger bar operatedin narrow angularly displaced radial slots formed in the rotor body,which slots delinedK the cam shape. In that arrangement the rotor bodyadjacent these slots extended beyond the end of the ca m so that, as theVrotor was snapped from one side to the other under the action of thespring pressed trip lever, the turning of the rotor was stopped, whenitV had reached the desired position, by engagement of the outwardlyprojecting rotor body portions, at

4 the sides of the cam, with the stop lug on the end of the plunger bar.

This resulted in the full load of the turning force or torque, appliesto the rotor by the trip lever, being received by the restraining lug,and, since the lug is merely an upturned projection on the end of theplunger bar, its structure would crystallize in a relatively short timeunder the repeated shock of operation and the lug would break offrendering the mechanism useless. Another difiiculty experienced with theformer beaver-tail cam arrangement was that often the stop lug wouldbecome engaged on the broad end surface of the cam and cause the carrierto become hung in a dead center or partially turned position so that itsaction was not always positive. This resulted in an incomplete switchoperation which in an emergency was very dangerous as, instead of dimmedhead-lights, there would be no light at all.

It is, therefore, the purpose of the present invention to cure thesedifticulties by improving the form of the cam portion of the rotox` andthe arrangement of the limit stop means so that the stop or lock lug onthe end of the plunger bar is wholly relieved of any shock load in theoperation of the mechanism; and so that operation of the mechanism iscertain at all times.

This is accomplished by providing the cam, as heretofore described, witha substantially diamond or rhombic shape and by providing sufficientopen space in the rotor body on either side of the cam so that the cambody can never engage the stop lug; and by providing independent, fixedstop means in the housing body for limiting the turning movement of therotor.

Thus, as shown in the drawings, the rhombicshaped cam I8 engages thestop lug IS with a sliding motion only, the lug I9 serving the solepurpose of restraining rotation of the rotor against the action of thetrip lever I0 until the plunger bar 6 has moved inwardly a suiiicientdistance to move the lug I9 beyond the tip of the cam I8 at which pointthe rotor 4 is released to complete its turning motion with a snapaction. In the Vform shown, the stop means for limiting the turningmovement of the rotor 4 comprises a pair of pillars or impact columns 20and 2| formed integrally with the body of the housing I and located atthe end thereof through which the trip lever extends. These stopelements 20 and 2| project inwardly into the path of the rotor wings, soas to engage the respective wings edgewise when the rotor has turned toits maximum desired extent. l

The cutaway or open portions 22 and 23 of the rotor, on either sideofthe cam I8, are of sutilcient width so that when the rotor has reachedits maximum position of turning, in either direction, no part of therotor will be engaged with the lug I9. In this manner the shock of thesnap action of the rotor 4 is absorbed entirely by the stop elements 20and 2|, and since the shock load is imparted to the stop elements in thedirection of their respective axes, there is no danger of the stopelements failing because of repeated shock blows. Thus, since the rotorrestraining or stop lug I9 receives no shock load whatsoever, there isno danger of its being broken and the operating life of the mechanism isincreased many times over that of the previous construction. Alsobecause the tip ofthe cam is substantially a point, being only slightlyrounded, it is virtually impossible for the stop lug to engage the endof the cam and hold the rotor in a partially turned position; regardlessofth'emanner V'ofoperation #of theplunger bar. K

'The operation ofthe yimproved Amechanism is lillustrated byFigs. 3- to6 inclusive, which show the position orr the parts, sequentially,through "one cycle of operation. The neutral or starting position isIshown in Fig. '2. lIn Fig. 3, the plunger bar' Bhas been pressed--inwardly to the point where vthe-inner end of the trip leverl I0 isswung laterally bythe -tooth I'I andfseated in the'seat or notch I5. Atthis point, the rotor-restraining andlocklug I9 has'progressed abouthalfway of the `length of the' engaged surface of the cam I8 duringwhich time it has held the rotor 4 in rvits initial or startingposition. Y

"-In`Fig. 4, the parts vare shown in the position `just"-prior to theinstant `of `release of the rotor, where the lplunger bar 6 'hasmoved'inwardly a sulcien't distance to shiftthe restraining-or' stop lugI9 to substantially the endfofy the cam I8. By this time the rotor hasbegun to turn, restrained,"however, by engagement with the lug I9, andthetrip lever Il) has vmov-ed baok-wardly along the plunger bar E andagainst the actionof 'the spring I4 so that the maximum power has beenstored up in the trip lever I9 Afor imparting a snap action torque tothe rotor 4. Thus, as the lock lug 'I9 passes beyond the end-of the camI8, the rotor vII is released and the trip lever I0', `under the actionof its spring I4, causes the rotor to move with a sudden snap actionuntil it is stopped by engagement of the adjacent rotor wing -w'ith thelsto'pelement 2|, asshown in Fig. 5. When this action has occurred thepressure against the plunger cap 8 is released and the plunger parts arereturned yby thefspring 9 to their neutral position shown in'Fig. 6.v Atthis position the lock lug I9 is seated at the base of the camY `I8 inthe cutaway portion 22 to Ahold the-rotor 4l firmly in the position towhich it has been turned.

It will be seen, from Figs. 3, 4 and 5, that up to the instant ofrelease from the lug I9, the yrotor has turned lapproximately 45 orone-half `of yits total :angular movement, and-that upon release therotor only travels about 45 further before being stopped by therespective stop element or 2 I. Thus the extent of rotor movement underthe snap-action of the spring I4 is a minimum and considerably reducesthe shock impact on the rotor when it is stopped by the stop elements.This is one factor which materially reduces wear and greatly prolongsthe useful life of the mechamsm.

The main advantages of this invention, as before mentioned, reside inthe greatly increased operational life of the operating mechanism thatis afforded through relieving the stop lug of any shock load; and by thearrangement whereby all shock load is sustained by rigid stop pillarswhich are supported by the mechanism housing. Another particularadvantagewill be found in the improved rhombic shape o1A the rotor camwherein its tip is substantially pointed so as to practically obviateany possibility of the rotor becoming hung up in dead center position byengagement of the stop lug on the end of the cam.

Although but one specific embodiment of this invention is herein shownand described it will be understood that details of the constructionshown may be altered or omitted without departing from the spirit of'this invention as defined by the following claims.

I claim:

1. In a device of the class described comprising a pivotally mountedcarrier and a trip lever B normally disposed vradially -with respect ftothe pivot raxis of the carriervand inthe plane of -th'e carrier, saidtrip lever vhaving 'afree end-adjacent said carrier adapted toswing'laterally relative to its `normal radial alignmentwith1the'carri`er axis, a pair of2 angularly `spaced seat'sin the margin-of said carrier adjacent the free endof said trip leverymeans on saidcarrier between said seats for guiding the freeend of the-trip leverintoone of said vseats,vand means for shifting 'said trip Aleverradiallyr toward said 'carrier and lholding the free end Yof the triplever in resilient'pre'ssure engagement in one of said seats to'applya'torque pressure on said carrier, 'a cam projecting outwardlyiromthe 'margin of said carrier on the side thereof opposite seat seats, astop lug normally engaged with 'one side of said cam 'at the basethereof, means vfor shifting said stop lug outwardlyrelative to the axisof 'said carrierv and disengaging said stop lug from the outer vend'ofsaid cam `during resilient pressure engagement of said trip lever with'said carrier, and fixed stop means for limiting thesnap-actionturning'movement of said carrier under the iniluence of saidstop means comprising fixed rigid laterally vspaced impact columnsdisposed in the plane of said carrier, one on each side of the axisthereof, and engageable endwise with a respective edge of said carrierat a point intermediate said axis yand the respective lateralextremityof the carrier, said carrier having its margincut away on eachside of said cam to avoid carrier contact with said stop lug and lugshifting means when said `carrier reaches r`the limit of its turningmovement.

2. In Ya device of thefclass described comprising a pivotally mountedcarrier having laterally extending portions on each side of the pivotaxis, and a trip lever normally disposed radiallyV with respect-.to thepivot axis and in the plane of the carrier, said trip lever having afree end adjacent said carrier adapted to swing laterally relative toits normal radial alignment with the carrier axis, a pair of angularlyspaced seats inA the margin of said carrier between said lateral portionand adjacent the free end of said trip lever, means between said seatsfor guiding the free end of the trip lever into one of said seats, andcompression spring means for shifting said trip lever radially towardsaid carrier and holding the free end of the trip lever in resilientpressure engagement in one of said seats to apply a turning torque onsaid carrier, a cam projecting radially from the margin of said carrieropposite said seats, said cam having a substantially rhombio shape withits margins in the plane of said carrier, a shiftable stop lug normallyengaged with the edge of said cam at the base thereof, the innerconverging margins of said cam being substantially radial relative tothe rotor axis, means for shifting said stop lug radially outwardrelative to the axis of said carrier and disengaging said lug from thetip of said cam during the resilient pressure engagement of said triplever with said carrier, and xed stop means cooperate with the lateralportions of said carrer for limiting the turning movement thereof uponrelease of said stop lug from said cam, said stop means comprising apair of iixed laterally spaced impact columns disposed in the plane ofsaid carrier, one on each side of the axis thereof, and extending intothe path of the respective lateral portions of the carrier forengagement with intermediate substantially radial portions thereof, andsaid car- 7 rier having its margin cut away on each side of said cam toavoid contact of said carrier with said stop lug when said carrierreaches the end of its turning movement.

3. In a device of the class described, a carrier mounted for rotation ona central axis and comprising a flat body having a pair of oppositelyextending lateral wing members, a tooth projecting radially from themargin of said body midway between said wing members and having inwardlydiverging sides, a seat in the margin of said body at each side of saidtooth and at the inner ends of the sides thereof, and a substantiallyrhombic-shaped cam projecting radi- :ally from the margin of said bodydiametrically opposite said tooth, the adjacent edges of said cam andsaid wing members diverging outwardly and said cam terminating in arounded tip, means adapted to engage in said seats alternately and applya resilient turning force to said carrier in respectively oppositedirections, a radially shiftable stop lug disposed to normally engagesaid cam along the side thereof toward which the turning force on saidcarrier is exerted, means for shifting said stop lug outwardly beyondthe cam tip to release said cam, and xed laterally spaced stop membersin the plane of said carrier and independent of said stop lug and lugshifting means for engaging intermediate radial edge portions of saidcarrier wing members respectively to limit the turning movement of saidcarrier in either direction.

4. A device of the class described comprising a housing having arotatable carrier therein mounted on a pivot post secured to the Wall ofthe housing, a plunger bar extending transversely of said pivot post andhaving a longitudinal slot through which said post extends whereby saidplunger bar may be reciprocated radially relative to said post, saidplunger bar and carrier being disposed on said post one above the other,a trip lever extending lengthwise of said plunger bar in the plane ofsaid carrier and having a free end adapted to engage the margin of saidcarrier to cause rotation thereof, said trip lever having 8 its outerend slidably mounted on said plunger for limited outward movementlengthwise thereof and adapted to permit lateral swinging movement ofthe free end ofthe trip lever, a pair of angularly spaced seats in themargin of said carrier adjacent the free end of said trip lever andmeans between said seats for guiding the free end of said trip leverinto one of the seats upon movement of said plunger bar and trip levertoward said pivot post, resilient means for normally holding the triplever on the centerline of said plunger and permitting outward movementof said trip lever along said plunger upon engagement of the trip leverwith said carrier, and means normally urging said plunger radiallyoutward relative to said pivot post, a cam member on the margin of saidcarrier opposite said seats, said cam member being of substantiallyrhombic shape and terminating in a rounded tip, a stop lug on saidplunger extending into the path of said cam member, said cam memberbeing adapted to engage said stop lug and resist movement of saidcarrier under the influence of said trip lever until said plunger hasbeen moved a. predetermined distance radially relative to said pivotpost, and a fixed stop member on said housing positioned to engage anintermediate radial edge portion of said carrier and limit its turningmovement upon disengagement of the stop lug and the tip of said cammember, said carrier being relieved on each side of said cam member toavoid engagement of the carrier with said stop lug at the end of itsturning movement.

GILBERT S. ELLITHORPE.

REFERENCES CITED The following references are of record in the iile ofthis patent:

UNITED STATES PATENTS Number Name Date 1,726,897 Horn a Sept. 3, 19292,179,252 Douglas Nov. 7, 1939 2,321,212 Johnson June 8, 1943

